1 /* Load a shared object at runtime, relocate it, and run its initializer.
2 Copyright (C) 1996-2004, 2005 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
28 #include <sys/mman.h> /* Check whether MAP_COPY is defined. */
29 #include <sys/param.h>
30 #include <bits/libc-lock.h>
39 /* Giving this initialized value preallocates some surplus bytes in the
40 static TLS area, see __libc_setup_tls (libc-tls.c). */
41 size_t _dl_tls_static_size = 2048;
44 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
45 void (*dl_main) (const ElfW(Phdr) *phdr,
47 ElfW(Addr) *user_entry));
48 weak_extern (BP_SYM (_dl_sysdep_start))
50 extern int __libc_multiple_libcs; /* Defined in init-first.c. */
52 /* Undefine the following for debugging. */
53 /* #define SCOPE_DEBUG 1 */
55 static void show_scope (struct link_map *new);
58 /* We must be carefull not to leave us in an inconsistent state. Thus we
59 catch any error and re-raise it after cleaning up. */
65 /* This is the caller of the dlopen() function. */
66 const void *caller_dlopen;
67 /* This is the caller if _dl_open(). */
68 const void *caller_dl_open;
72 /* Original parameters to the program and the current environment. */
80 add_to_global (struct link_map *new)
82 struct link_map **new_global;
83 unsigned int to_add = 0;
86 /* Count the objects we have to put in the global scope. */
87 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
88 if (new->l_searchlist.r_list[cnt]->l_global == 0)
91 /* The symbols of the new objects and its dependencies are to be
92 introduced into the global scope that will be used to resolve
93 references from other dynamically-loaded objects.
95 The global scope is the searchlist in the main link map. We
96 extend this list if necessary. There is one problem though:
97 since this structure was allocated very early (before the libc
98 is loaded) the memory it uses is allocated by the malloc()-stub
99 in the ld.so. When we come here these functions are not used
100 anymore. Instead the malloc() implementation of the libc is
101 used. But this means the block from the main map cannot be used
102 in an realloc() call. Therefore we allocate a completely new
103 array the first time we have to add something to the locale scope. */
105 if (GL(dl_ns)[new->l_ns]._ns_global_scope_alloc == 0)
107 /* This is the first dynamic object given global scope. */
108 GL(dl_ns)[new->l_ns]._ns_global_scope_alloc
109 = GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist + to_add + 8;
110 new_global = (struct link_map **)
111 malloc (GL(dl_ns)[new->l_ns]._ns_global_scope_alloc
112 * sizeof (struct link_map *));
113 if (new_global == NULL)
115 GL(dl_ns)[new->l_ns]._ns_global_scope_alloc = 0;
117 _dl_signal_error (ENOMEM, new->l_libname->name, NULL,
118 N_("cannot extend global scope"));
122 /* Copy over the old entries. */
123 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list
124 = memcpy (new_global,
125 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list,
126 (GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist
127 * sizeof (struct link_map *)));
129 else if (GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist + to_add
130 > GL(dl_ns)[new->l_ns]._ns_global_scope_alloc)
132 /* We have to extend the existing array of link maps in the
134 new_global = (struct link_map **)
135 realloc (GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list,
136 ((GL(dl_ns)[new->l_ns]._ns_global_scope_alloc + to_add + 8)
137 * sizeof (struct link_map *)));
138 if (new_global == NULL)
141 GL(dl_ns)[new->l_ns]._ns_global_scope_alloc += to_add + 8;
142 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list = new_global;
145 /* Now add the new entries. */
146 for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)
148 struct link_map *map = new->l_searchlist.r_list[cnt];
150 if (map->l_global == 0)
153 GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list[GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist]
155 ++GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_nlist;
164 dl_open_worker (void *a)
166 struct dl_open_args *args = a;
167 const char *file = args->file;
168 int mode = args->mode;
169 struct link_map *new, *l;
173 bool any_tls = false;
175 struct link_map *call_map = NULL;
177 /* Check whether _dl_open() has been called from a valid DSO. */
178 if (__check_caller (args->caller_dl_open,
179 allow_libc|allow_libdl|allow_ldso) != 0)
180 _dl_signal_error (0, "dlopen", NULL, N_("invalid caller"));
182 /* Determine the caller's map if necessary. This is needed in case
183 we have a DST, when we don't know the namespace ID we have to put
184 the new object in, or when the file name has no path in which
185 case we need to look along the RUNPATH/RPATH of the caller. */
186 const char *dst = strchr (file, '$');
187 if (dst != NULL || args->nsid == __LM_ID_CALLER
188 || strchr (file, '/') == NULL)
190 const void *caller_dlopen = args->caller_dlopen;
192 /* We have to find out from which object the caller is calling.
193 By default we assume this is the main application. */
194 call_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
196 for (Lmid_t ns = 0; ns < DL_NNS; ++ns)
197 for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)
198 if (caller_dlopen >= (const void *) l->l_map_start
199 && caller_dlopen < (const void *) l->l_map_end)
201 /* There must be exactly one DSO for the range of the virtual
202 memory. Otherwise something is really broken. */
203 assert (ns == l->l_ns);
209 if (args->nsid == __LM_ID_CALLER)
212 /* In statically linked apps there might be no loaded object. */
213 if (call_map == NULL)
214 args->nsid = LM_ID_BASE;
217 args->nsid = call_map->l_ns;
221 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
223 /* Maybe we have to expand a DST. */
224 if (__builtin_expect (dst != NULL, 0))
226 size_t len = strlen (file);
230 /* DSTs must not appear in SUID/SGID programs. */
231 if (INTUSE(__libc_enable_secure))
232 /* This is an error. */
233 _dl_signal_error (0, "dlopen", NULL,
234 N_("DST not allowed in SUID/SGID programs"));
237 /* Determine how much space we need. We have to allocate the
239 required = DL_DST_REQUIRED (call_map, file, len, _dl_dst_count (dst, 0));
241 /* Get space for the new file name. */
242 new_file = (char *) alloca (required + 1);
244 /* Generate the new file name. */
245 _dl_dst_substitute (call_map, file, new_file, 0);
247 /* If the substitution failed don't try to load. */
248 if (*new_file == '\0')
249 _dl_signal_error (0, "dlopen", NULL,
250 N_("empty dynamic string token substitution"));
252 /* Now we have a new file name. */
255 /* It does not matter whether call_map is set even if we
256 computed it only because of the DST. Since the path contains
257 a slash the value is not used. See dl-load.c. */
260 /* Load the named object. */
261 args->map = new = _dl_map_object (call_map, file, 0, lt_loaded, 0,
262 mode | __RTLD_CALLMAP, args->nsid);
264 /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
265 set and the object is not already loaded. */
268 assert (mode & RTLD_NOLOAD);
272 if (__builtin_expect (mode & __RTLD_SPROF, 0))
273 /* This happens only if we load a DSO for 'sprof'. */
276 /* This object is directly loaded. */
277 ++new->l_direct_opencount;
279 /* It was already open. */
280 if (__builtin_expect (new->l_searchlist.r_list != NULL, 0))
282 /* Let the user know about the opencount. */
283 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
284 _dl_debug_printf ("opening file=%s [%lu]; opencount=%u\n\n",
285 new->l_name, new->l_ns, new->l_opencount);
287 /* If the user requested the object to be in the global namespace
288 but it is not so far, add it now. */
289 if ((mode & RTLD_GLOBAL) && new->l_global == 0)
290 (void) add_to_global (new);
292 if (new->l_direct_opencount == 1)
293 /* This is the only direct reference. Increment all the
294 dependencies' reference counter. */
295 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
296 ++new->l_searchlist.r_list[i]->l_opencount;
298 /* Increment just the reference counter of the object. */
301 assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);
306 /* Load that object's dependencies. */
307 _dl_map_object_deps (new, NULL, 0, 0,
308 mode & (__RTLD_DLOPEN | RTLD_DEEPBIND | __RTLD_AUDIT));
310 /* So far, so good. Now check the versions. */
311 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
312 if (new->l_searchlist.r_list[i]->l_real->l_versions == NULL)
313 (void) _dl_check_map_versions (new->l_searchlist.r_list[i]->l_real,
321 /* Auditing checkpoint: we have added all objects. */
322 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
324 struct link_map *head = GL(dl_ns)[new->l_ns]._ns_loaded;
325 /* Do not call the functions for any auditing object. */
326 if (head->l_auditing == 0)
328 struct audit_ifaces *afct = GLRO(dl_audit);
329 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
331 if (afct->activity != NULL)
332 afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);
340 /* Notify the debugger all new objects are now ready to go. */
341 struct r_debug *r = _dl_debug_initialize (0, args->nsid);
342 r->r_state = RT_CONSISTENT;
345 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
346 lazy = (mode & RTLD_BINDING_MASK) == RTLD_LAZY && GLRO(dl_lazy);
348 /* Relocate the objects loaded. We do this in reverse order so that copy
349 relocs of earlier objects overwrite the data written by later objects. */
356 if (! l->l_real->l_relocated)
359 if (GLRO(dl_profile) != NULL)
361 /* If this here is the shared object which we want to profile
362 make sure the profile is started. We can find out whether
363 this is necessary or not by observing the `_dl_profile_map'
364 variable. If was NULL but is not NULL afterwars we must
365 start the profiling. */
366 struct link_map *old_profile_map = GL(dl_profile_map);
368 _dl_relocate_object (l, l->l_scope, 1, 1);
370 if (old_profile_map == NULL && GL(dl_profile_map) != NULL)
372 /* We must prepare the profiling. */
373 _dl_start_profile ();
375 /* Prevent unloading the object. */
376 GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE;
381 _dl_relocate_object (l, l->l_scope, lazy, 0);
389 /* Increment the open count for all dependencies. If the file is
390 not loaded as a dependency here add the search list of the newly
391 loaded object to the scope. */
392 for (i = 0; i < new->l_searchlist.r_nlist; ++i)
393 if (++new->l_searchlist.r_list[i]->l_opencount > 1
394 && new->l_real->l_searchlist.r_list[i]->l_type == lt_loaded)
396 struct link_map *imap = new->l_searchlist.r_list[i];
397 struct r_scope_elem **runp = imap->l_scope;
400 while (*runp != NULL)
402 /* This can happen if imap was just loaded, but during
403 relocation had l_opencount bumped because of relocation
404 dependency. Avoid duplicates in l_scope. */
405 if (__builtin_expect (*runp == &new->l_searchlist, 0))
413 /* Avoid duplicates. */
416 if (__builtin_expect (cnt + 1 >= imap->l_scope_max, 0))
418 /* The 'r_scope' array is too small. Allocate a new one
420 struct r_scope_elem **newp;
421 size_t new_size = imap->l_scope_max * 2;
423 if (imap->l_scope == imap->l_scope_mem)
425 newp = (struct r_scope_elem **)
426 malloc (new_size * sizeof (struct r_scope_elem *));
428 _dl_signal_error (ENOMEM, "dlopen", NULL,
429 N_("cannot create scope list"));
430 imap->l_scope = memcpy (newp, imap->l_scope,
431 cnt * sizeof (imap->l_scope[0]));
435 newp = (struct r_scope_elem **)
436 realloc (imap->l_scope,
437 new_size * sizeof (struct r_scope_elem *));
439 _dl_signal_error (ENOMEM, "dlopen", NULL,
440 N_("cannot create scope list"));
441 imap->l_scope = newp;
444 imap->l_scope_max = new_size;
447 imap->l_scope[cnt++] = &new->l_searchlist;
448 imap->l_scope[cnt] = NULL;
451 else if (new->l_searchlist.r_list[i]->l_opencount == 1
452 /* Only if the module defines thread local data. */
453 && __builtin_expect (new->l_searchlist.r_list[i]->l_tls_blocksize
456 /* Now that we know the object is loaded successfully add
457 modules containing TLS data to the slot info table. We
458 might have to increase its size. */
459 _dl_add_to_slotinfo (new->l_searchlist.r_list[i]);
461 if (new->l_searchlist.r_list[i]->l_need_tls_init)
463 new->l_searchlist.r_list[i]->l_need_tls_init = 0;
465 /* Update the slot information data for at least the
466 generation of the DSO we are allocating data for. */
467 _dl_update_slotinfo (new->l_searchlist.r_list[i]->l_tls_modid);
470 GL(dl_init_static_tls) (new->l_searchlist.r_list[i]);
471 assert (new->l_searchlist.r_list[i]->l_need_tls_init == 0);
474 /* We have to bump the generation counter. */
478 /* Bump the generation number if necessary. */
479 if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0))
480 _dl_fatal_printf (N_("\
481 TLS generation counter wrapped! Please report this."));
484 /* Run the initializer functions of new objects. */
485 _dl_init (new, args->argc, args->argv, args->env);
487 /* Now we can make the new map available in the global scope. */
488 if (mode & RTLD_GLOBAL)
489 /* Move the object in the global namespace. */
490 if (add_to_global (new) != 0)
494 /* Mark the object as not deletable if the RTLD_NODELETE flags was
496 if (__builtin_expect (mode & RTLD_NODELETE, 0))
497 new->l_flags_1 |= DF_1_NODELETE;
500 /* We must be the static _dl_open in libc.a. A static program that
501 has loaded a dynamic object now has competition. */
502 __libc_multiple_libcs = 1;
505 /* Let the user know about the opencount. */
506 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
507 _dl_debug_printf ("opening file=%s [%lu]; opencount=%u\n\n",
508 new->l_name, new->l_ns, new->l_opencount);
513 _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,
514 int argc, char *argv[], char *env[])
516 struct dl_open_args args;
518 const char *errstring;
521 if ((mode & RTLD_BINDING_MASK) == 0)
522 /* One of the flags must be set. */
523 _dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()"));
525 /* Make sure we are alone. */
526 __rtld_lock_lock_recursive (GL(dl_load_lock));
528 if (nsid == LM_ID_NEWLM)
530 /* Find a new namespace. */
531 for (nsid = 1; nsid < DL_NNS; ++nsid)
532 if (GL(dl_ns)[nsid]._ns_loaded == NULL)
537 /* No more namespace available. */
538 __rtld_lock_unlock_recursive (GL(dl_load_lock));
540 _dl_signal_error (EINVAL, file, NULL, N_("\
541 no more namespaces available for dlmopen()"));
544 _dl_debug_initialize (0, nsid)->r_state = RT_CONSISTENT;
546 /* Never allow loading a DSO in a namespace which is empty. Such
547 direct placements is only causing problems. Also don't allow
548 loading into a namespace used for auditing. */
549 else if (nsid != LM_ID_BASE && nsid != __LM_ID_CALLER
550 && (GL(dl_ns)[nsid]._ns_nloaded == 0
551 || GL(dl_ns)[nsid]._ns_loaded->l_auditing))
552 _dl_signal_error (EINVAL, file, NULL,
553 N_("invalid target namespace in dlmopen()"));
557 args.caller_dlopen = caller_dlopen;
558 args.caller_dl_open = RETURN_ADDRESS (0);
564 errcode = _dl_catch_error (&objname, &errstring, dl_open_worker, &args);
567 /* We must munmap() the cache file. */
571 /* Release the lock. */
572 __rtld_lock_unlock_recursive (GL(dl_load_lock));
574 if (__builtin_expect (errstring != NULL, 0))
576 /* Some error occurred during loading. */
577 char *local_errstring;
578 size_t len_errstring;
580 /* Remove the object from memory. It may be in an inconsistent
581 state if relocation failed, for example. */
584 /* Increment open counters for all objects since this
585 sometimes has not happened yet. */
586 if (args.map->l_searchlist.r_list[0]->l_opencount == 0)
587 for (unsigned int i = 0; i < args.map->l_searchlist.r_nlist; ++i)
588 ++args.map->l_searchlist.r_list[i]->l_opencount;
591 /* Maybe some of the modules which were loaded use TLS.
592 Since it will be removed in the following _dl_close call
593 we have to mark the dtv array as having gaps to fill the
594 holes. This is a pessimistic assumption which won't hurt
595 if not true. There is no need to do this when we are
596 loading the auditing DSOs since TLS has not yet been set
598 if ((mode & __RTLD_AUDIT) == 0)
599 GL(dl_tls_dtv_gaps) = true;
602 _dl_close (args.map);
605 /* Make a local copy of the error string so that we can release the
606 memory allocated for it. */
607 len_errstring = strlen (errstring) + 1;
608 if (objname == errstring + len_errstring)
610 size_t total_len = len_errstring + strlen (objname) + 1;
611 local_errstring = alloca (total_len);
612 memcpy (local_errstring, errstring, total_len);
613 objname = local_errstring + len_errstring;
617 local_errstring = alloca (len_errstring);
618 memcpy (local_errstring, errstring, len_errstring);
621 if (errstring != INTUSE(_dl_out_of_memory))
622 free ((char *) errstring);
624 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
626 /* Reraise the error. */
627 _dl_signal_error (errcode, objname, NULL, local_errstring);
630 assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);
633 DL_STATIC_INIT (args.map);
644 show_scope (struct link_map *new)
648 for (scope_cnt = 0; new->l_scope[scope_cnt] != NULL; ++scope_cnt)
653 numbuf[0] = '0' + scope_cnt;
655 _dl_printf ("scope %s:", numbuf);
657 for (cnt = 0; cnt < new->l_scope[scope_cnt]->r_nlist; ++cnt)
658 if (*new->l_scope[scope_cnt]->r_list[cnt]->l_name)
659 _dl_printf (" %s", new->l_scope[scope_cnt]->r_list[cnt]->l_name);
661 _dl_printf (" <main>");